A non-reflecting wave equation through directional wave-field suppression and its finite difference implementation

A non-reflecting wave equation through directional wave-field suppression and its finite difference implementation

Schaeken, Teun (Student TU Delft)
Hoogerbrugge, L.A. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Computational Imaging)
Verschuur, D.J. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Imaging Physics)

ImPhys/Imaging Physics

2022

The acoustic wave equation describes wave propagation directly from basic physical laws, even in heterogeneous acoustic media. When numerically simulating waves with the wave equation, contrasts in the medium parameters automatically generate all scattering effects. For some applications - such as propagation analysis or certain wave-equation based imaging techniques - it is desirable to suppress these reflections, as we are only interested in the transmitted wave-field. To achieve this, a modification to the constitutive relations is proposed, yielding an extra term that suppresses waves with reference to a preferred direction. The scale-factor α of this extra term can either be interpreted as a penetration depth or as a typical decay time. This modified theory is implemented using a staggered-grid, time-domain finite difference scheme, where the acoustic Poynting-vector is used to estimate the local propagation direction of the wave-field. The method was successfully used to suppress reflections in media with bone tissue (medical ultrasound) and geophysical subsurface structures, while introducing only minor perturbations to the transmitted wave-field and a small increase in computation time.

OA-Fund TU Delft

http://resolver.tudelft.nl/uuid:53fe67a8-b08f-4a13-b255-c5659d74b47b

https://doi.org/10.1038/s41598-021-04064-3

2045-2322

Scientific Reports, 12 (1)

Institutional Repository

journal article

© 2022 Teun Schaeken, L.A. Hoogerbrugge, D.J. Verschuur